# Maths help integration

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#2

Try differentiating your indefinite answer and compare with the question?

Looks like a tan() type substitution to me.

Looks like a tan() type substitution to me.

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#4

(Original post by

Try differentiating your indefinite answer and compare with the question?

Looks like a tan() type substitution to me.

**mqb2766**)Try differentiating your indefinite answer and compare with the question?

Looks like a tan() type substitution to me.

Yazomi; don't remove the fraction and make it a negative power - that may be helpful to do

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**mqb2766**)

Try differentiating your indefinite answer and compare with the question?

Looks like a tan() type substitution to me.

(Original post by

I think you forgot to integrate what’s inside the bracket?

**ㅋㅋㅋㅋㅋ**)I think you forgot to integrate what’s inside the bracket?

Hmm after tan substitution I got

And I think the answers a bit dodgy

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#6

Your initial integral was in terms of x, so I would expect you to set and proceed from there. Where did u come from?

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(Original post by

Yeah, It looks like an arctan(x) outcome somewhere along the line..

Yazomi; don't remove the fraction and make it a negative power - that may be helpful to do

**ThatsAGoodOne349**)Yeah, It looks like an arctan(x) outcome somewhere along the line..

Yazomi; don't remove the fraction and make it a negative power - that may be helpful to do

I’m not sure if this is what you mean but I’ve got this instead?

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(Original post by

I don't even know what you're doing there!

Your initial integral was in terms of x, so I would expect you to set and proceed from there. Where did u come from?

**davros**)I don't even know what you're doing there!

Your initial integral was in terms of x, so I would expect you to set and proceed from there. Where did u come from?

Here’s the question is it helps

I was trying to do part be but I was trying to see if I could still find out the area without using the cos^2 theta given.

I think the part I messed up was trying to figure out what to put u=

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#9

I don't mean to be rude, but how long have you been studying integration? Are you getting support from a teacher or self-studying?

You've posted a number of integration questions recently where you seem to have invented rules for integration that just aren't valid, instead of following standard methods like recognition, substitution and IBP. This is leading you into all sorts of problems later on

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#11

Also man you gotta relearn integration from the ground up. I don't know how you're going from int((1+x^2)^-2)dx to -(1+x^2)^-1 + c but, in the nicest way possible, it shows that there are serious gaps in your understanding of how integration works. At this point you're inventing your own rules for integration, which aren't even remotely correct. Try TLMaths, ExamSolutions, Zeeshaan Zamurred, or some other maths teacher who makes videos on youtube, whoever you vibe best with.

EDIT: looking at a more recent post, my man this is worse than not understanding integration. Go back to GCSE maths, I'm not trying to be mean but if you don't understand fractions how are you going to be able to do integration?

Last edited by Filthy Communist; 2 weeks ago

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Oh dear welp I’ll start practising some more. I don’t think I’ll be prepared for the mock tmr 😂

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#13

(Original post by

Oh dear welp I’ll start practising some more. I don’t think I’ll be prepared for the mock tmr 😂

**Yazomi**)Oh dear welp I’ll start practising some more. I don’t think I’ll be prepared for the mock tmr 😂

https://www.drfrostmaths.com/uploads...CheatSheet.pdf

is decent, but an aid rather than substitute for practice.

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(Original post by

The cheatsheet

https://www.drfrostmaths.com/uploads...CheatSheet.pdf

is decent, but an aid rather than substitute for practice.

**mqb2766**)The cheatsheet

https://www.drfrostmaths.com/uploads...CheatSheet.pdf

is decent, but an aid rather than substitute for practice.

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#15

(Original post by

Ahhh thankssss it’s looking really helpful so far

**Yazomi**)Ahhh thankssss it’s looking really helpful so far

When you think you've done the indefinite integrals, try differentiating them to check it gives the original function, if you've got time.

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#16

And also note you can instantly check definite integrals with your calculator, assuming you cave the 991-EX or CG-50

It does it numerically, so it will give a decimal answer. Subtract that answer from what you got and if you get 0 you did it right.

It does it numerically, so it will give a decimal answer. Subtract that answer from what you got and if you get 0 you did it right.

Last edited by Filthy Communist; 2 weeks ago

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(Original post by

And also note you can instantly check definite integrals with your calculator, assuming you cave the 991-EX or CG-50

It does it numerically, so it will give a decimal answer. Subtract that answer from what you got and if you get 0 you did it right.

**Filthy Communist**)And also note you can instantly check definite integrals with your calculator, assuming you cave the 991-EX or CG-50

It does it numerically, so it will give a decimal answer. Subtract that answer from what you got and if you get 0 you did it right.

(Original post by

It's a bit basic, but something to build on.

When you think you've done the indefinite integrals, try differentiating them to check it gives the original function, if you've got time.

**mqb2766**)It's a bit basic, but something to build on.

When you think you've done the indefinite integrals, try differentiating them to check it gives the original function, if you've got time.

For a question like this how do you know what to use as a substitute or it’s really just guess work?

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#18

(Original post by

Alright got ya thanks

Just got one more quick question

For a question like this how do you know what to use as a substitute or it’s really just guess work?

**Yazomi**)Alright got ya thanks

Just got one more quick question

For a question like this how do you know what to use as a substitute or it’s really just guess work?

cos^2 = 1 - sin^2

1+x^2 hints at:

1 + tan^2 = sec^2

Last edited by mqb2766; 2 weeks ago

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(Original post by

1-x^2 sounds like the Pythagorean identity, as the limits also hint at (30-60-90 triangle). So something like cos^2 = 1 - sin^2

1 x^2 hints at:

1 tan^2 = sec^2

**mqb2766**)1-x^2 sounds like the Pythagorean identity, as the limits also hint at (30-60-90 triangle). So something like cos^2 = 1 - sin^2

1 x^2 hints at:

1 tan^2 = sec^2

！(◎_◎; )

Ok I’ll leave that for later. I don’t think I’ll be able to take on or even spot these hints in the actual thing

Last edited by Yazomi; 2 weeks ago

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#20

(Original post by

What on earth

！(◎_◎; )

Ok I’ll leave that for later. I don’t think I’ll be able to take on or even spot these hints in the actual thing

**Yazomi**)What on earth

！(◎_◎; )

Ok I’ll leave that for later. I don’t think I’ll be able to take on or even spot these hints in the actual thing

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